Green tea protects body against cancer and Alzheimer’s, study shows

ScienceDaily (Jan. 5, 2011) — Regularly drinking green tea could protect the brain against developing Alzheimer’s and other forms of dementia, and also a vital role in protecting the body against cancer, according to latest research by scientists at Newcastle University.

The study, published in the academic journal Phytomedicine.Led by Dr Ed Okello, the Newcastle team wanted to know if the protective properties of green tea — which have previously been shown to be present in the undigested, freshly brewed form of the drink — were still active once the tea had been digested.

Digestion is a vital process which provides our bodies with the nutrients we need to survive. But, says Dr Okello, it also means that just because the food we put into our mouths is generally accepted to contain health-boosting properties, we can’t assume these compounds will ever be absorbed by the body.

“What was really exciting about this study was that we found when green tea is digested by enzymes in the gut, the resulting chemicals are actually more effective against key triggers of Alzheimer’s development than the undigested form of the tea,” explains Dr Okello, based in the School of Agriculture, Food and Rural Development at Newcastle University. “In addition to this, we also found the digested compounds had anti-cancer properties, significantly slowing down the growth of the tumour cells which we were using in our experiments.”

Previous studies have shown that compounds known as polyphenols, present in black and green tea, possess neuroprotective properties, binding with the toxic compounds and protecting the brain cells. When ingested, the polyphenols are broken down to produce a mix of compounds and it was these the Newcastle team tested in their latest research.

“It’s one of the reasons why we have to be so careful when we make claims about the health benefits of various foods and supplements,” explains Dr Okello.

“There are certain chemicals we know to be beneficial and we can identify foods which are rich in them but what happens during the digestion process is crucial to whether these foods are actually doing us any good.”

Carrying out the experiments in the lab using a tumour cell model, they exposed the cells to varying concentrations of the different toxins and the digested green tea compounds.